The present invention generally relates to an electrical signal interface between an anesthesia machine and an anesthetic agent cassette. More specifically, the present invention relates to an electrical signal interface contained within a removable anesthetic agent cassette that allows the single, common anesthetic agent cassette to communicate using analog communication with a legacy, analog anesthesia machine and digital communication with a digital anesthesia machine.
During the supply of anesthesia, the gaseous anesthetic agent inhaled by the patient is formed of oxygen, nitrogen, nitrous oxide and an inhalation anesthetic agent. Inhalation anesthetics are typically in liquid form at administration temperatures, and an anesthetic vaporizer is needed to gasify the liquid. Anesthetic vaporizers have a drug reservoir for storing the supply of agent to be vaporized. The vaporized anesthetic is administered for the patient to inhale by means of a carrier gas flow.
Presently, many types of anesthesia machines receive an anesthetic vaporizer that can be configured in the shape of a cassette such that different cassettes can be easily removed and replaced from the anesthesia machine depending upon the type of anesthetic agent to be delivered. One example of such a cassette is the Aladin™ cassette available from Datex-Ohmeda, Inc. The anesthetic agent cassette includes electronic circuitry that monitors the liquid level of the anesthetic agent remaining within the reservoir. The electronic circuitry contained within the anesthetic agent cassette communicates back to the control circuitry of the anesthesia machine such that the anesthesia machine can signal to an operator when the level of anesthetic agent within the reservoir of the agent cassette falls below an acceptable value.
Presently, many of the anesthesia machines in use, such as the S/5 ADU Carestation® also available from Datex-Ohmeda, utilize analog communications between the electronic circuitry within the anesthetic agent cassette and the anesthesia machine. However, the analog communication technique utilized between the anesthesia machine and the agent cassette is being replaced by digital communications that allows additional information to be relayed between the anesthesia machine and the agent cassette.
Anesthetic agent cassettes being developed for use with newer anesthetic machines include enhanced measuring and reporting abilities that communicate using digital signals. In a hospital or critical care environment that utilizes the two types of anesthesia machines that communicate by analog or digital signals, the facility will be required to purchase and own two different types of anesthetic agent cassettes that can be utilized on either an analog anesthesia machine or a digital anesthesia machine. Therefore, a need exists for an anesthetic agent cassette that can be utilized with both an anesthesia machine using digital communications and an anesthesia machine using analog communications.